I. Field
The present invention relates generally to an electronics device, and more specifically to a multi-antenna wireless device.
II. Background
A multiple-input multiple-output (MIMO) communication system employs multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NT transmit antennas and NR receive antennas may be decomposed into NS spatial channels, where Ns≦min {NT, NR}. The NS spatial channels may be used to transmit data in parallel to achieve higher throughput and/or redundantly to achieve greater reliability.
A multi-antenna wireless device is equipped with multiple antennas that may be used for data transmission and/or reception. Each antenna may be associated with (1) transmit circuitry used to process a baseband output signal to generate a radio frequency (RF) output signal suitable for transmission via a wireless channel and (2) receive circuitry used to process an RF input signal to obtain a baseband input signal. The multi-antenna wireless device also typically has digital circuitry used to digitally process data for transmission and reception.
Due to the additional complexity associated with MIMO operation, the multi-antenna wireless device may be much more complex than a single-antenna wireless device in a system that can support both single-antenna and multi-antenna wireless devices. The multi-antenna wireless device may thus consume much more power than the single-antenna wireless device. The higher power consumption is undesirable, especially if the multi-antenna wireless device is a portable unit (e.g., a handset) that is powered by an internal battery. The higher power consumption depletes the available battery resources more quickly, which then shortens both the standby time between battery recharges and the on time for active communication.
There is therefore a need in the art for a multi-antenna wireless device that is power efficient.